Gateway selection controlled by network

ABSTRACT

A method, computer program product and a user equipment (UE) are provided for selecting a second network node for connection. A first message is sent to a first network node. The first message includes UE request capabilities. A second message is received from the first network node. The second message includes an indication. A second network node is selected for connecting to the network based on the received indication. The second network node may be an Evolved Packet Data Gateway (ePDG). The UE request capabilities may indicate ePDG selection and/or allow discovery of details of one or more ePDGs for connection. the indication contains at least one of a Fully Qualified Domain Name (FQDN) or an indication that the UE must attempt to connect using only an ePDG belonging to a Registered Public Land Mobile Network (RPLMN).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims priority from prior U.S. Provisional Patent Application No. 62/253,636, filed on Nov. 10, 2015, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND

Technical Field

The present disclosure generally relates to cellular network selection and more specifically to cellular network selection for a 3GPP device/user equipment (UE) to access an Enhanced Packet Core (EPC) via an access network that is not a 3GPP defined access network.

Description of the Related Arts

A Voice over Wi-Fi (VoWiFi) call requires connection to an Evolved Packet Data Gateway (ePDG), which in turn needs to be selected by the UE. In addition, Public Land Mobile Networks (PLMNs) may have Lawful Intercept (LI) obligations that they are compelled to respect by laws in the jurisdictions in which the PLMN operates. Therefore, when the UE roams into a country or region or legal jurisdiction that is not belonging to the UE's Home PLMN (HPLMN), there may be LI obligations that need to be met and require the UE to select and establish a connection to an ePDG residing in a Visited PLMN (VPLMN) within the visited country/legal jurisdiction. Problems arise in enforcing the obligations by the HPLMN, the VPLMN or both.

There is currently no means defined in existing standards whereby the VPLMN can inform the UE, or the UE verify with the VPLMN, whether the UE can be allowed to select a HPLMN ePDG instead of a VPLMN ePDG. There is also no behavior defined for what the UE is to do upon receipt of this information.

The lack of a means for verification presents several problems. For example, it is not known how the UE can be instructed to select an ePDG in the VPLMN by the VPLMN when the UE has attached (i.e. has a Registered PLMN (RPLMN) in memory) via 3GPP access to that PLMN. In addition, if the UE has not attached to a PLMN (i.e. the RPLMN has been deleted according to 3GPP TS 23.122, subclause 5), but has authenticated with a PLMN via wireless local area network (WLAN) there is no means for that PLMN to instruct the UE to select an ePDG in that VPLMN.

PLMNs are sometimes identified by a fully qualified domain name (FQDN) that is not constructed from a PLMN Identity (ID) as defined in 3GPP TS 23.002 (i.e. a Mobile Country Code (MCC) and a Mobile Network Code (MNC)). For example, a PLMN may purchase a service provider that was not a PLMN. As such, until such time as the PLMN can operationally upgrade the infrastructure, there will be a period of time when a PLMN is advertised using non-PLMN codes. Current mechanisms have been identified as being an acceptable way to enforce LI in some circumstances, however these mechanisms only allow PLMN IDs to be provisioned and, as such, if a PLMN has LI requirements but advertises itself via a FQDN, there is no way for the HPLMN to configure this PLMN in the current data set.

Also, a VPLMN may identify its ePDGs via FQDNs, and a UE may only select an ePDG in a VPLMN using PLMN ID/code or Tracking Area (TA)/Location Area (LA), yet the FQDN is associated with an ePDG. There is currently no means to provision the UE to select an ePDG using such an FQDN to allow the VPLMN to meet its LI obligations via existing mechanisms.

Finally, if a solution is deployed to resolve the above problems, there is a possibility a VPLMN might abuse the mechanism to mandate the UE to use an ePDG in the VPLMN when the VPLMN has no LI requirement in order to capture potential lost roaming revenue.

BRIEF SUMMARY

In one embodiment, a method in a user equipment (UE) to select a second network node is disclosed. The method comprises sending a first message to a first network node, the first message including UE request capabilities; receiving a second message from the first network node, the second message containing an indication; and selecting a second network node for connecting to a network based on the received indication.

In another embodiment, a user equipment for selecting a second network node is disclosed. The user equipment comprises a communication interface communicatively coupled to a processor. The communication interface sends a first message to a first network node. The first message includes UE request capabilities. The communication interface further receives a second message from the first network node. The second message contains an indication. The processor selects a second network node for connecting to the network based on the received indication.

In yet another embodiment, a computer program product for selecting a second network node for a user equipment to connect to a network is disclosed. The computer program product comprises a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for sending a first message to a first network node, the first message including UE request capabilities; receiving a second message from the first network node, the second message containing an indication; and selecting a second network node for connecting to the network based on the received indication.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views, and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present disclosure, in which:

FIG. 1 is a diagrammatic view illustrating one example of how an Extensible Authentication Protocol (EAP) framework may be used in a cellular device in accordance with prior art;

FIG. 2 illustrates one example of a message flow diagram for Dynamic Host Configuration Protocol (DHCP) in accordance with prior art;

FIG. 3 is block diagram of a WLAN system using Access Network Query Protocol (ANQP) in accordance with prior art;

FIG. 4 is a block diagram of an example architecture for cell broadcast service;

FIG. 5 is another block diagram of an example architecture for cell broadcast service;

FIG. 6 is an operational flow diagram illustrating one example of a method of receiving an ePDG selection indicator via Location Area Update (LAU) Accept, Routing Area Update (RAU) Accept, Tracking Area Update (TAU) Accept or Attach Accept, in accordance with one embodiment of the present disclosure;

FIG. 7 is an operational flow diagram illustrating one example of a method of receiving an ePDG selection indicator via Protocol Configuration Options (PCO), in accordance with one example of the present disclosure;

FIG. 8 is an operational flow diagram illustrating one example procedure for a UE to receive an ePDG selection indicator using WLAN ANQP, in accordance with one example of the present disclosure;

FIG. 9 is an operational flow diagram illustrating one example procedure for a UE to receive an ePDG selection indicator using EAP, in accordance with one example of the present disclosure;

FIG. 10 is an example data model illustrating how a Lawful Intercept (LI) policy could be stored in an application according to one example of the present disclosure; and

FIG. 11 is a block diagram illustrating an example UE in accordance with one example of the present disclosure.

DETAILED DESCRIPTION 1. System Environment

1.1 Introduction

When a 3GPP device/UE accesses an Enhanced Packet Core/Evolved Packet System (EPC/EPS) core via an access network that is not a 3GPP defined access network (e.g., where a 3GPP access network could be a GSM EDGE (GERAN), Universal Terrestrial Radio Access Network (UTRAN) or Evolved UTRAN (E-UTRAN)), the UE needs to select and then establish a connection with an ePDG. The methods described herein may also be implemented using a software client (e.g., an “app”) running on a 3GPP device/UE. A UE may comprise a mobile equipment (ME) and a Universal Integrated Circuit Card (UICC). Furthermore, an ME may be implemented as a combination of software blocks, wherein the functionality described herein could be a standalone block, or a combination of the operating system and underlying software stacks used to support wireless operations, with the RF apparatus being a separate function. In addition, a UE may also be referenced herein as a mobile device, or a mobile station (MA or STA). The terms UE and 3GPP device/user equipment are used predominately within the application, however the term ME can equally be interchanged with them. The following subsections describe different aspects and predicates for a UE to access an EPC via non-3GPP access.

1.2 Trusted Access

Trusted access may also be known as S2a access. The UE performs WLAN Access Authentication and Authorization (AAA). In this step, the UE receives a trust indicator from the network in the EAP signaling that is used as part of the Authentication and Authorization step. If the trust indicator indicates the network is trusted the UE uses trusted network access procedures as described in 3GPP TS 24.302.

1.3 Non-Trusted Access

Non-trusted access may also be known as S2b access. Once the UE has connected to a WLAN and Internet Protocol (IP) connectivity has been established on the connected-to WLAN (e.g., an IP address has been obtained, for example, using DHCP), then the UE sets up secure tunnel, (e.g., an Internet Protocol Security (IPsec) tunnel) to a network function or network element called an Evolved Packet Data Gateway (ePDG). The ePDG terminates (i.e. acts as an end point to) the IPsec tunnel and selects a Packet Data Network Gateway (P-GW) based on a parameter provided by the UE. ePDG selection is described in more detail in this document in section “1.5 ePDG selection.”

In connecting to the WLAN and before establishing IP connectivity, the UE may perform WLAN Access Authentication and Authorization using EAP signaling (see section “1.4 EAP”) or other means (e.g., splash screens or “capture portal,” pre-shared key, username/password (which may use a AAA/RADIUS/Diameter server), etc.).

1.4 EAP

The Extensible Authentication Protocol, as the name suggests, is an extensible authentication framework. EAP provides the necessary tools to incorporate other authentication schemes into the basic messaging structure. There are numerous different EAP mechanisms defined. A diagrammatic view 100 of how the EAP framework can be used in a cellular device can be seen in FIG. 1.

3GPP defines 3 EAP methods that can be used in a UE: EAP-AKA, EAP-SIM and EAP-AKA′. The EAP-SIM authentication mechanism has been generally considered by those expert in the subject area to have been compromised and therefore no longer safe to use, so only EAP-AKA and EAP-AKA′ can be used to access an EPC/EPS core network.

Once EAP authentication has been successful, the UE can establish IP connectivity from the Wi-Fi network (e.g., using DHCP). Once IP connectivity has been established on the Wi-Fi network, an ePDG can be selected.

1.5 ePDG Selection

1.5.1 General

The ePDG that can be selected to be connected to by the UE can either be in the Visited PLMN (VPLMN) or the Home PLMN (HPLMN). The VPLMN is generally defined herein to indicate a PLMN whose Mobile Country Code (MCC), Mobile Network Code (MNC) does not match the MCC, MNC stored in either EF_(IMSI) or EF_(EHPLMN), both of which are specified in 3GPP TS 31.102. The HPLMN is generally defined herein to indicate a PLMN whose MCC, MNC does match the MCC, MNC stored in either EF_(IMSI) as specified in 3GPP TS 31.102, or stored in EF_(EHPLMN). Other potential HPLMNs can be Equivalent HPLMNs (EHPLMNs) and Equivalent PLMNs (EPLMNs). An EHPLMN is equivalent to a HPLMN and its identities are stored in EF_(EHPLMN), specified in 3GPP TS 31.102. An EPLMN is equivalent to a Registered PLMN (i.e. the PLMN that the UE has successfully attached to), and its identities are received in an Attach Accept, Location Update Accept, Location Area Update Accept, Routing Area Update Accept and a Tracking Area Update Accept from the RPLMN.

The HPLMN has the ability to provision information within the UE to aid the UE in selecting the ePDG (e.g., via Open Mobile Alliance Device Management (OMA DM), via configuration on the Universal Subscriber Identity Module (USIM) (which could itself be provisioned there via OTA methods), etc).

1.5.2 Static Configured Address

The UE may be configured with static ePDG information. This information may consist of one or more IP addresses, a Fully Qualified Domain Name (FQDN) code, or a PLMN code. An FQDN is used as input into a Domain Name Service (DNS) query to retrieve one or more IP addresses.

1.5.3 Dynamic Address Creation

A more concise version of dynamic address creation functionality can be found in 3GPP TS 23.402 sub-section 4.5.4. or in C1-153983. If static ePDG information is not available to the UE, the HPLMN may provision ePDG selection information. ePDG selection information may consist of provisioning zero to many PLMN IDs, and against each PLMN ID is an indicator to indicate how the UE shall construct an FQDN (which in turn is resolved to one or more IP addresses, e.g. using DNS) and another indicator to be used in the event that the UE is unable to establish a connection to the ePDG in a VPLMN identified by the constructed FQDN (which was resolved to one or more IP addresses), that indicates if the HPLMN ePDG can be selected to establish a connection.

If the UE attaches to a PLMN (known as the RPLMN), and this RPLMN is not the HPLMN and is in the list of PLMN IDs, then the UE selects the ePDG in that RPLMN. If selection fails, depending on another parameter, the UE may try and select the ePDG in the HPLMN or PLMN selection may stop. The HPLMN can also provision a wild card entry in this list, whereby if the UE is roaming and the VPLMN ID is not in the PLMN list but the wild card entry is present in the PLMN list, then the UE will use the wild card entry to determine how to select the ePDG in the VPLMN. If ePDG selection in the VPLMN fails, depending on another indicator, the UE may select an ePDG in the HPLMN or may stop ePDG selection altogether.

1.6 Protocol Configuration Options (PCO)

Protocol Configuration Options (PCO) is a general name given to a capability that was first used in General Packet Radio System (GPRS). PCO allows a device, via a number of indicators (wherein an indicator can consist of one or more bits, or even the absence of one or more bits, in a message), to indicate to the network some information the UE requires. The network would respond back with information pertaining to the requested information and/or information not requested. The request and response mechanism was called PCO. This capability was later extended to UTRAN, Long Term Evolution (LTE) and E-UTRAN, and then also WLAN networks via Internet Key Exchange (IKE) signaling during ePDG connection establishment. Some data types that a UE can request and be provided with are described in 3GPP TS 24.008 subsection 10.5.6.3 (e.g., Proxy Call Server Control Function (P-CSCF) addresses, Network based IP Flow Mobility (NBIFOM) mode, IP Flow Mobility (IFOM) support, etc.).

PCO is defined in 3GPP TS 24.008 subclause 6.1.3.7, 3GPP 24.301 subclause 6.6.1 and 3GPP TS 24.302 subclause 6.9 and 6.4.3.5.2. In 3GPP accesses (e.g., GERAN, UTRAN, E-UTRAN) the PCO information comes from a Gateway GPRS Support Node (GGSN), or P-GW. The GGSN or P-GW can be located in the VPLMN or HPLMN. The GGSN or P-GW may be configured with the information (e.g., via operator operations and maintenance procedures) or obtain the information by some other means.

1.7 Voice Over Wi-Fi

When a UE makes a Voice over Wi-Fi (VoWiFi) call, the device first has to select an ePDG to access the EPC network that will connect to the IP Multimedia Subsystem (IMS) network. ePDG selection has been described above in section “1.5 ePDG selection.” After ePDG selection has been performed, the UE creates a tunnel to the selected ePDG, and eventually performs an IMS/SIP REGISTRATION as described in 3GPP TS 24.229 with an IMS network that connects to the EPC network if the UE wants to use operator IMS services. After the IMS REGISTRATION has completed, the UE can make a voice call.

1.8 Lawful Intercept (LI)

When a UE is in a country there might be a need to perform Lawful Interception (LI) for calls that originated from that UE. LI is performed by intercepting the UE traffic in the network that the UE has attached to, the RPLMN or the network or PLMN that hosts the ePDG used in the same country. The access network and the core network are usually owned by the same entity or network or PLMN, or in the case of network sharing there is a business relationship between those two entities. Voice over LTE (VoLTE), entities and/or functions that may be used to intercept the traffic are the Mobility Management Entity (MME), the Serving Gateway (S-GW), the P-GW, the S-CSCF, the Media Gateway (MGW), etc. For circuit switched calls, the Mobile Switching Center (MSC) can be used to intercept traffic.

1.9 Dynamic Host Configuration Protocol (DHCP)

DHCP is used in an IP network in order to dynamically configure network hosts with data/parameters (e.g., IP addresses, DNS servers, default gateway, etc.). The message flow for DHCP is shown in the flow diagram 200 of FIG. 2.

The DHCP client 202, which may reside/be hosted on a UE, broadcasts a Discover message 206 to the connected-to network (e.g., sends the Discover message to an IPv4 address of 255.255.255.255). One or more DHCP servers 204 (one shown) may respond to the client 202 with a DHCP Offer message 208, which contains one or more parameters (e.g., IP address).

In response to one of the DHCP Offers 208 the client 202 receives, the client 202 broadcasts a DHCP Request message 210 accepting the chosen DHCP Offer 208, and in this broadcast message there may be included some parameters requesting further configuration data/parameters.

In response to the received DHCP Request 210 that the DHCP Server 204 who sent the associated DHCP Offer 208 receives, the DHCP Server 204 sends a DHCP Acknowledgement 212 (also known as a DHCP ACK), which may contain such information as lease duration and any other configuration data/information that the client 202 may have requested. The DHCP client 202, upon receiving the DHCP Acknowledge 212, configures the host (e.g., the UE) appropriately with the received parameters for the interface upon which the DHCP transaction took place. Some basic DHCP options are defined by the Internet Engineering Task Force (IETF) in IETF RFC 2132, and further options are specified in further IETF specifications.

DHCP can be used in Internet Protocol version 4 (IPv4) networks and Internet Protocol version 6 (IPv6 networks), in which case DHCPv4 and DHCPv6 nomenclature is used. DHCPv6 has the following message names in place of those in FIG. 2 above: Solicit, Advertise, Request, and Reply.

1.10 WLAN ANQP (Access Network Query Protocol)

Generic Advertisement Service (GAS) is used as a transport mechanism for various advertisement protocols, including Access Network Query Protocol (ANQP). Each advertisement protocol connects the mobile device to one of several servers (e.g., the “Access Network Information” server) that can be located in the LAN to which an Access Point (AP) is connected or within the AP itself.

The advertisement protocol allows the bidirectional transmission of frames between a mobile device and a server in the network prior to network connectivity, so that the mobile device is effectively in a pre-associated state. Thus, a mobile device is connected to the layer 2 radio service, but has not exchanged any authentication parameters and does have a recognized session (e.g., no session keys are establishment and no IP address is assigned.) Therefore, according to the IEEE 802.11 standard, no user plane data traffic is allowed in this state and any signaling information is insecure and cannot be guaranteed. Any data/messages from the access point is considered as “hint” information by the mobile device, until authentication is complete, when this information can be verified if required.

As GAS operates between the mobile device and the AP being terminated in each entity, the AP is responsible for the relay of the mobile device's advertisement protocol to a server in the network and for delivering the server's response back to the mobile device.

The IEEE 802.11 Access Network Query Protocol (ANQP) is one example of an advertisement protocol transported between mobile stations (STAs) and access points (APs). The STA is the equivalent of a UE. The architecture of the WLAN system 300 is shown in FIG. 3. ANQP operates as a simple query and response protocol that is used by a mobile device 302 to discover a range of information from an Access Network (AN) server 304. This AN server 304 is either co-located with an Access Point (AP) 306 or is located within the Local Area Network (LAN), which is the layer 2 network to which the AP 306 is connected.

ANQP allows a mobile device 302 (e.g., STA, UE, MS) to determine the properties of the LAN before starting or at any time after starting the association procedure. Information obtained through ANQP can include: network identifiers, roaming relationships, supported security methods (e.g., IEEE 802.1X and web-based authentication), emergency services capability, available service providers, etc. This ability enables ANQP to be a very powerful protocol capable of discovering information about WLANs, prior to the mobile device 302 establishing network connectivity.

Currently there are about 23 individual ANQP-elements that have been defined in IEEE 802.11 and the Wi-Fi Alliance Hotspot 2.0 program, each one capable of retrieving different information from the LAN, for example: AP Location, AP Venue Name, Service Provider availability, etc.

To discover each ANQP element, the UE (STA) 302 sends an ANQP Request 308 to the AP 306 with an integer identifier (Info ID) corresponding to the desired information report. The AP 306 then responds with an information element containing that information report. For example, the UE 302 sends the integer 265 in an ANQP Request 308 to the AP 306 to obtain the location (latitude and longitude) information of that AP 306 in an ANQP Response message.

1.11 Cell Broadcast

Cell Broadcast is a broadcast technology that was developed for GSM and has been adapted to both UTRAN and E-UTRAN systems. Cell Broadcast allows a device to listen to a known logical control channel on the radio interface and receive messages. Broadcast messages can be marked for specific services and or broadcast in specific regions and can be cyclic in nature, meaning they are repeated. FIGS. 4 and 5 show two architectures 400, 500 out of three for Cell Broadcast service (CBS). The key differences are that in FIG. 4, the Radio Access Network 402 connects to the Cell Broadcast Centre (CBC) 404, where in FIG. 5 the core network, MME 502, connects to the CBC 504.

CBS provides a framework for messages to be either displayed to the user (via MessageID 4370) or consumed by an application within the device (via MessageID 0-4351).

1.12 MBMS

Multimedia Broadcast/Multicast Service (MBMS) is a 3GPP broadcast technology that is similar to CBS, but MBMS allows an operator to deliver more data intensive content to a group of users (e.g., TV, video, etc.). MBMS is supported by GERAN, UTRAN and E-UTRAN. MBMS over E-UTRAN is referred to as eMBMS and is described in 3GPP TS 36.300.

MBMS supports two basic transmission modes for delivering IP packets: broadcast and multicast. The MBMS Broadcast mode can be used to deliver IP packets to all terminals in a certain area or the whole network. If the MBMS broadcast mode is used, a transmission bearer is setup for all cells in which the service should be available and is continuously transmitting as long as the service is up and running. In broadcast mode, MBMS does not require an uplink connection and can thus be used like any other “downlink-only” broadcast technology (e.g., Digital Video Broadcasting-Handheld (DVB-H), Digital Video Broadcasting-Terrestrial (DVB-T), Digital Multimedia Broadcasting (DMB), etc.).

The MBMS Multicast mode works very similar to IP multicasting. A terminal which wants to receive information related to a particular multicast channel “joins” one or several content channels (e.g., expresses interest to receive content associated with this channel). This information is processed in the routing layer of the core network and is used for optimizing the data delivery path. “Optimizing” means that data is transmitted just once over connections shared by receivers of the same multicast channels. The only drawback of multicasting is the additional delay when switching from one channel to another one. Therefore, MBMS multicasting is less suitable for mobile TV services which usually require a low TV channel switching delay. The main application of MBMS multicasting is for download services or music casting services.

MBMS was specified such that broadcast/multicast services can be used together with voice and data services within the same radio carrier. This arrangement gives the greatest flexibility to cellular operators.

1.13 Network Selection

Network Selection for a UE is defined in 3GPP TS 23.122. A UE can be registered in a network or not registered in a network. When a UE successfully registers in a network, the UE stores the registered network, known as RPLMN within memory. The RPLMN is the PLMN ID (Mobile Country Code, Mobile Network Code) received in the Attach Accept from the network. This RPLMN is stored in memory even if the UE is out of radio coverage. The RPLMN is deleted from memory under specific conditions. These conditions are shown in Table 1 of the Appendix attached, which quotes 3GPP TS 23.122.

2. Embodiments

A number of solutions for network selection (e.g., cellular network selection) for a 3GPP device/user equipment to access an EPC via an access network that is not a 3GPP defined access network are presented in this section. Solutions generally include one or more means/methods of receiving an access node (e.g., ePDG) selection indicator as well as one or more means/methods of using the access node (e.g., ePDG) selection indicator. One will appreciate that the solutions below can be mixed and matched to create further embodiments. Also, some of the solutions identify that a UE might support or be requesting VoWLAN. These solutions may equally be used for requesting ePDG support or requesting ePDG support. Those skilled in the art will appreciate that an ePDG is a node that provides access to the core network and the ePDG could be considered an “access node”. For the purposes of the description below the term “access node” could be equally used for ePDG.

2.1 3GPP Request/Response Mechanisms Attach, LAU, RAU, TAU

Solutions for instructing an UE to select an ePDG in the VPLMN by the VPLMN when the UE has attached to a PLMN (i.e. the UE has an RPLMN in memory) via 3GPP access to that PLMN are discussed in this subsection.

2.1.1 Receipt of ePDG Selection Indicator Via Location Area Update (LAU) Accept, Routing Area Update (RAU) Accept, Tracking Area Update (TAU) Accept, Attach Accept

FIG. 6 is an operational flow diagram 600 illustrating an example process for selecting a network node by way of receiving an ePDG selection indicator via at least one of but not limited to LAU Accept, RAU Accept, TAU Accept or Attach Accept, etc. The UE 602 may perform the procedure below when first attaching to the network or the UE 602 may request an ePDG selection indicator when there is an indication that Wi-Fi connectivity has either been requested or Wi-Fi connectivity has been obtained or achieved. This indication could be, for example, that the UE 602 has an IP address from the WLAN or the UE 602 has an IP address and has determined that internet is available (e.g., the UE 602 has pinged and a result has been returned from a known URL).

The ePDG selection indicator could be one of the following:

-   1. A single bit to indicate that ePDG selection is required in the     VPLMN or that ePDG selection is not required in the VPLMN. In other     words, VoWLAN is supported, or VoWLAN is not supported. -   2. An information element containing the FQDN of the ePDG to use for     ePDG selection. -   3. An information element containing an IP address of the ePDG to     use for ePDG selection.

It should be noted that options 2 and 3 perform the same function as option 1; however, the support of ePDG selection in the PLMN or the lack of support of ePDG selection in the PLMN is conveyed by the presence of the FQDN/IP address or the absence of the FQDN/IP address.

It should also be noted that FIG. 6 includes system components of an LTE system for completeness purposes (e.g., eNodeB 603, MME 604, MSC 605, P-GW 606, network node 607, Policy & Charging Rule Function (PCRF) 608, and Home Subscriber Server (HSS) 609); however, each component shown may or may not have an active role in the procedures described herein.

The UE 602 begins the process by sending, at step 610, a first message (Message#1) to a first network node (Network Node #1) MME 604. Message#1 contains a private user identity and, optionally, “UE request capabilities.” In the example shown in FIG. 6, Message#1 is an Attach Request; however, Message#1 620 could also be a LAU, a RAU, a TAU, or an ANQP Query. In addition, Network Node #1 is shown as MME 604; however, Network Node #1 could also be MSC 604, a Serving GPRS Support Node (not shown), an AAA (not shown), a DNS server (not shown), an ANQP server (not shown), an DHCP server (not shown), etc.

Examples of a private user identity include an IMSI, a Temporary Mobile Subscriber Identity (TMSI), a Packet Temporary Mobile Subscriber Identity (P-TMSI), a Global Unique Temporary ID (GUTI), a Network Access Identifier (NAI), Globally Unique Temporary ID (GUTI), etc.

“UE request capabilities” defines a single or group of indicators indicating: a) ePDG selection and/or b) VoWiFi (i.e. VoWLAN). The VoWiFi could be a set of indicators that could be set, for example, in an existing field, giving voice domain preference to either: a) IMS over WLAN voice only, b) IMS over LTE preferred, c) IMS over WLAN secondary, or d) IMS over LTE secondary, IMS over WLAN preferred.

Network Node #1 604 receives Message#1, optionally containing the “UE request capabilities,” and determines if the UE 602 should select an ePDG in a specific PLMN (such as a current PLMN, a PLMN in which the MME is located, the PLMN named in the Attach Request, a VPLMN, P-GW 606, etc.) in the event the UE attempts to use or uses untrusted WLAN access (e.g., with S2b, the UE wishes to establish an Internet Key Exchange (IKE or IKEv2) security association and the UE does not use dual stack mobile IPV6 when attempting to establish the IKEv2 security association, when the UE attaches to the EPC via WLAN IP access). This determination may be performed by examining the international mobile subscriber identity (IMSI) and/or receipt of ePDG data from a third network node (Network Node #3) (e.g., HSS 609). In the case shown in FIG. 6, Network Node #1 (MME 604) sends, at step 612, an Update Location Request (ULR) (i.e. Message#2) to Network Node #3 (HSS 609). The Network Node #3 (HSS 609) responds, at step 614, by sending an Update Location Answer (ULA) (i.e. Message#3) back to Network Node #1 (MME 604). The ULA includes an information element containing an indication that the received IMSI from the Network Node #3 (HSS 609) also has ePDG/VoWLAN capabilities.

Network Node #1 (MME 604) sends, at step 616, Message#4 back to the UE 602. In the case of FIG. 6, Message#4 is an Attach Accept; however, Message#4 may also be a LAU Accept, an RAU Accept, a TAU Accept or an ANQP Response. Message#4 contains a ePDG selection indicator if the UE 602 should select the ePDG in the VPLMN, or does not contain the ePDG selection indicator if the UE 602 should select the ePDG in the VPLMN.

UE 602 receives Message#4 containing the ePDG selection indicator indicating whether ePDG selection should be performed and, optionally, a location identifier (e.g., a Location Area/Routing area/tracking area identity).

As mentioned previously, the above procedure is described for when a UE 602 attaches to the network. However, the above procedure may also be performed after a normal Attach, thus when there is an indication that the UE's Wi-Fi radio has been turned on or Wi-Fi connectivity has been achieved (i.e. an IP address has been assigned to the UE from a Wi-Fi network) the UE 602 will perform a Location Area Update/Tracking Area Update/Routing Area update and perform the above procedure. The above procedure may be implemented using the following proposed changes to 3GPP TS 24.301 shown in Table 2. Proposed additions in all Tables include herein are indicated by underlined text. Proposed deletions are indicated by strikethrough text.

Table 3 shows proposed changes to 3GPP TS 24.008 detailing one possible embodiment of how the UE request capabilities may be encoded. In this example, the UE request capabilities are conveyed as a set of indicators. The UE request capabilities could equally be conveyed as a single flag/bit, so using the example below, a spare bit in octet 3 could be used or another information element or information element in a response message (e.g., Attach Accept LAU accept, RAU accept, etc.).

2.1.2 Receipt of ePDG Selection Via PCO

FIG. 7 is an operational flow diagram 700 illustrating an example process for selecting a network node by way of receiving an ePDG selection indicator via Protocol Configuration Options (PCO). Note that the system components are the same or similar to components previously shown in FIG. 6 for purposes of completeness (i.e. UE 602, eNodeB 603, MME 604, MSC 605, P-GW 606, network node 607, PCRF 608, and HSS 609); however, each component shown may or may not have an active role in the procedures described herein.

The UE 602 begins the process by sending, at step 702, Message#1 to a first network node (Network Node #1) illustrated in FIG. 7 as MME 604. Although Network Node #1 is shown in FIG. 7 as MME 604, Network Node #1 may also be an MSC an SGSN, an AAA, a DNS Server, a DHCP Server, and the like. Message#1 contains a private user identity and, optionally the “UE request capabilities.”

Network Node#1 receives Message#1 and if the private user identity has no associated subscriber profile at Network Node #1, sends, at step 704, Message#2a to a second network node (Network Node #2) illustrated in FIG. 7 as P-GW 606. Network Node #2 may be a GGSN. Message#2a could be a message used to create the Packet Data Protocol (PDP) context for VoLTE (i.e. Message#2a may contain the “well known IP Multimedia Subsystem Access Point Name (IMS APN)”). Message#2a contains the private user identity and if received Message#1 contained the “UE request capabilities,” Message#2a will also contain these UE request capabilities.

Network Node #2 receives Message#2a containing the optional “UE request capabilities.” Based either on the “UE request capabilities,” if present, and/or the APN that is being used, Network Node #2 obtains the policy for the connection (e.g., by consulting with an external database that could be the PCRF 608).

Network Node #2 sends, at step 706, Message#2b to a third network node (Network Node #3) shown in FIG. 7 as P-GW 606. Message#2b may include an optional indication that VoWLAN is supported. In other words, the indication means that the IMSI is authorized to make VoWLAN calls. It should be noted that this indicator could equally be called “non-3GPP access allowed.” Network Node #3 receives Message#2b and, based upon the content, at step 708, sends Message#3a containing the policy to be used for ePDG selection/VoWLAN. Message#3a contains an ePDG selection indicator as described above.

Network Node #2 receives Message#3a containing the ePDG selection indicator and Network Node #2 sends, at step 710, Message#3b containing Message#3a ePDG selection indicator. Network Node #2 sends, at step 712, the received ePDG selection indicator to the UE in Message#4. Finally, UE 602 receives Message#4 containing the ePDG selection indicator.

The above procedure may be implemented using the following proposed changes to 3GPP TS 24.008 shown in Table 4. Proposed changes are indicated by underlined text. MS to network direction information is present in Message#1 and Message#2a. Network to MS direction information is present in Message#3b and Message#4.

Table 5 represents an embodiment of Message#2b and Message#3a by implementing proposed changes to 3GPP TS 29.212.

Table 6 presents proposed changes to 3GPP TS 23.401.

2.1.3 Use of ePDG Selection Indicator

The indication received from the network may be stored in UE memory against the PLMN ID (i.e. RPLMN) that provided the indication (e.g., the PLMN ID can be derived from Tracking/Routing/Location area identity received in an Accept message. The indication shall be deleted from UE memory if the RPLMN is deleted/marked as not valid per 3GPP TS 23.122 subclause 5 (i.e. there is no registered PLMN).

If the UE has stored an ePDG selection indicator in memory and that ePDG selection indicator indicates to select an ePDG in RPLMN the UE ignores any information provisioned as described in section “1.5 ePDG selection” according to known methods.

If a single bit was received to indicate that ePDG selection is required in the VPLMN or ePDG selection is not required in the VPLMN (i.e. VoWLAN is supported, or VoWLAN is not supported), then if the RPLMN is the HPLMN and the UE has the ePDG identifier provisioned in the ePDG configuration information, then the UE uses the ePDG configuration information. If a single bit was received and the RPLMN is in the ePDG configuration information as specified in 3GPP TS 23.402, then the UE constructs an FQDN using the RPLMN ID stored in memory and the policy stored against that RPLMN ID as per 3GPP TS 23.402. Finally, if a single bit was received and the RPLMN is not in the ePDG configuration information as specified in 3GPP TS 23.402, but an equivalent PLMN as received in the Attach Accept is in the ePDG configuration information as specified in 3GPP TS 23.402, then the UE constructs an FQDN using the last registered PLMN ID stored in memory or equivalent PLMN ID.

However, if an FQDN was received, the UE uses that FQDN in contacting the ePDG. The FQDN shall be used as input to DNS query to obtain IP address of the ePDG. If an IP address was received, the UE shall use the IP address to contact the ePDG. The UE uses the IP address to set-up an IPSec tunnel to the ePDG.

If selection of the ePDG fails in the VPLMN the UE will then use static ePDG information to contact the ePDG; or construct an FQDN using the MCC, MNC of the IMSI stored in the EF_(IMSI) file on the USIM.

Table 7 presents one example of proposed changes to 3GPP TS 23.402 for use of the ePDG selection indicator.

Table 8 presents a second example of proposed changes to 3GPP TS 23.402.

Table 1 makes reference to Updated state in 3GPP TS 23.122. This text could be replaced with the other states and specifications as described in Table 9.

In addition, Table 10, below, makes reference to “Non-access stratum layer as defined in 3GPP TS 24.301,” which can be replaced or “Or'd” with “Non-access stratum layer as defined in 3GPP TS 24.008” or removed from the text.

Table 11 represents the second example, proposing alternate changes to 3GPP TS 24.302 based on other aspects.

2.2 Broadcast Information

Another example provides a different method which uses broadcast information for instructing an UE to select an ePDG in the VPLMN by the VPLMN when the UE has attached to a PLMN (i.e. the UE has an RPLMN in memory) via 3GPP access to that PLMN in this subsection.

2.2.1 Receipt of ePDG Selection Indicator

Network broadcasts system information. System information contains ePDG selection indicator. Other implementations the ePDG information may be broadcast using Cell Broadcast/CBS or MBMS.

The UE receives Broadcast Information/CBS/MBMS that contains the ePDG selection indicator. The UE stores the ePDG selection indicator against the PLMN ID code received in the broadcast information that contained the ePDG selection indicator or in corresponding system information that was broadcast.

The UE may be in CONNECTED, IDLE or Limited-Service State when it receives the Broadcast information. If the UE is turned off the ePDG selection indicator is deleted. As an option, receipt of ePDG selection indicator in broadcast system information might result in the UE also performing one of the methods of section 2.1 to obtain the ePDG selection indicator. For example, the broadcast ePDG selection indicator may be a flag to indicate ePDG address is available. The UE would perform a method of section 2.1 to obtain the specific ePDG address.

2.2.2 Use of ePDG Selection Indicator

Use of the ePDG selection indicator operates in the same manner as described above in section 2.1.3.

2.3 WLAN ANQP

A WLAN ANQP may be used to enable a PLMN to instruct the UE to select an ePDG in a VPLMN if the UE has not attached to a PLMN (i.e. the RPLMN has been deleted according to 3GPP TS 23.122 subclause 5), but has authenticated with a PLMN via WLAN.

2.3.1 Receipt of ePDG Selection Indicator

FIG. 8 illustrates an operational flow diagram 800 showing a procedure for a UE to receive an ePDG selection indicator using WLAN ANQP in accordance to one example of the present disclosure. The UE 802 sends, at step 810, message #1 to Network Node #1 804. Network Node #1 804 may be an Access Point and message #1 may be an ANQP request. Network Node #1 804 receives the message #1. Message #1 may contain Additional UE Provided Information.

Upon receiving Message #1, Network Node #1 804 may send, at step 812, Message #2 to Network Node #2 806. Message #2 may be, for example, a CC-Request. Message #2 may contain Additional UE Provided Information if received in Message #1. Network Node #2 806 may be an advertisement server for ANQP. It should be noted that the functionality of Network Node #2 806 may be co-located with Network Node #1 804, so that Message #2 and Message #3 become internal messages within Network Node #1 804. Upon receiving Message #2, Network Node #2 806 sends, at step 814, Message #3 to Network Node #1 804. Message #3 may be a CC-Answer and may contain one or both of Routing Data and/or an error message. Upon receiving Message #3, Network Node #1 804 sends, at step 816, Message #4 to UE 802. Message #4 may be, for example, an ANQP Response containing one or both of Routing Data and/or an error message depending on what was received in Message #3.

The underlined text in Table 12 represents changes to the Wi-Fi Alliance Hotspot 2.0 (Release 2) Technical Specification Version 1.0.1.

2.3.2 Use of ePDG Selection Indicator

Use of the ePDG selection indicator operates in the same manner as described above in section 2.1.3.

2.4 EAP Procedure

EAP may also be used to enable a PLMN to instruct the UE to select an ePDG in a VPLMN if the UE has not attached to a PLMN (i.e. the RPLMN has been deleted according to 3GPP TS 23.122 subclause 5), but has authenticated with a PLMN via WLAN.

2.4.1 Receipt of ePDG Selection Indicator

FIG. 9 illustrates an operational flow diagram 900 showing a procedure for a UE to receive an ePDG selection indicator using EAP in accordance with one example of the present disclosure. It should also be noted that FIG. 9 includes system components of a network for completeness purposes (e.g., UE 902; ePDG 904; X-CSCF 906; Authentication, Authorization and Accounting (AAA) server 908 and HSS 912); however, each component shown may or may not have an active role in the procedures described herein. It should be noted that X-CSCF 906 could be a P-CSCF, an S-CSCF, or an I-CSCF).

The UE 902 sends, at step 920, an authentication message to the AAA server 908 containing one to many identities, including a Public User Identity. AAA server 908 receives the authentication message from the UE 902 containing one to many identities and determines if the UE 902 should select an ePDG in that PLMN. This determination may optionally be performed by sending, at step 922, a message containing the Public User Identity (i.e. Message#2) to an external database, such as HSS 912, and HSS 912 responds, at step 924, by sending a message (i.e. Message#3) containing challenge vectors for the Public User Identity contained in Message#2 and a Request Private ID indicating whether the requested ePDG selection indicator is supported, back to AAA server 908.

The AAA server 908 sends, at step 926, an authentication message (i.e. Message #4) to the UE 902 containing a parameter “ePDG selection indicator supported.” This parameter indicates that the AAA server 908 can send “ePDG selection indicator” in a later authentication message. The UE 902 sends, at step 928, an authentication response message (i.e. Message #5) to the AAA server 908 containing an indication (e.g., “ePDG_request”) that ePDG address is required. The AAA server 908 receives, from the UE 902, the authentication message containing an ePDG selection indicator indicating that an ePDG address is required (i.e. Message #5). The AAA server 908 may optionally request the ePDG address from an external database, such as HSS 912, by sending, at step 930, an authentication message (i.e. Message #6) containing the ePDG selection indicator to the external database. In this case, the AAA server 908 receives, at step 932, the ePDG address in an ePDG selection indicator from the external database as an acknowledgement message (e.g., as an ePDG_RESP). The AAA server 908 sends, at step 934, an authentication message to the UE 902 containing the ePDG selection indicator with ePDG address. At step 936, the UE 902 uses the ePDG address received in step 934 to setup a secure tunnel to the ePDG. This may consist of sending an ePDG FQDN to a DNS server so that the FQDN can be resolved into an IP address of the ePDG. At step 938, the UE 902 performs a standard IMS REGISTRATION with the P-SCSF/S-CSCF 906.

Table 13 presents proposed changes to 3GPP TS 24.302 for implementing this example method.

2.4.2 Use of ePDG Selection Indicator

Use of the ePDG selection indicator operates in the same manner as described above in section 2.1.3.

2.5 ePDG selection enhancement

Another example method works in conjunction with the above methods to prevent the possibility that a VPLMN might abuse the mechanism to mandate the UE to use an ePDG in the VPLMN when the VPLMN has no LI requirement to capture potential lost roaming revenue.

In this example, the UE now has an LI policy stored in either the USIM, or the Home Access Network Discovery and Selection Function (H-ANDSF). The LI policy includes a list of entries, 0 to many, that contains an identity and an action that should be performed if that identity matches. The identity may be a PLMN ID, an MCC, an FQDN, an NAI, an IP address or a wildcard. The action may be mandatory or optional. If an entry in the LI policy contains the action “mandatory,” the UE shall use the ePDG selection indicator provided by the RPLMN. If an entry in the LI policy contains the action “optional,” the UE shall not use the ePDG selection indicator provided by the RPLMN.

2.5.1 Receipt of the ePDG Selection Indicator

Any of the methods described herein may be used in conjunction with the method of section 2.5.2 to receive the ePDG selection indicator.

2.5.2 Use of ePDG Selection Indicator

The actions of the UE are dependent upon the attachment of the UE. If the UE has attached to a PLMN via 3GPP or has not attached to a PLMN via 3GPP access and has authenticated with a PLMN via WLAN access and that PLMN is contained within the LI policy, the actions are further dependent upon the LI policy. If the PLMN has a policy of “mandatory,” then the UE shall follow the procedures as described above in section 2.1.3. If the PLMN has a policy of “optional,” then the UE shall follow the procedures as described in 3GPP TS 23.402 sub-section 4.5.4.

If the UE was not attached to a PLMN and when setting up a connection to an ePDG will use an FQDN, IP address or NAI that has an entry in the LI policy. If that entry in the LI policy has an action of “mandatory,” then the UE shall follow the procedures as described in section 2.13. If that entry has an action of “optional,” then the UE shall follow the procedures as described in 3GPP TS 23.402 sub-section 4.5.4.

Table 14 shows proposed changes to 3GPP TS 23.402 to implement this method. The bold text represents the difference between that described in section 2.1.3 and the proposed changes.

Table 15 shows proposed changes to 3GPP TS 24.312 illustrating how the LI policy may be stored in the UE. The LI policy could equally be stored in an application on the UICC (e.g., USIM) using the data model shown in FIG. 10.

2.6 DHCP

In one example method, DHCP is used to instruct the UE to select an ePDG in the VPLMN by the VPLMN when the UE has attached (has an RPLMN in memory) via 3GPP access to that PLMN (e.g., when the connected-to WLAN is carrier-owned). In addition, if the UE has not attached to a PLMN (i.e. the RPLMN has been deleted according to 3GPP TS 23.122 subclause 5), but has authenticated with a PLMN via WLAN, DHCP is used to instruct the UE to select an ePDG in that VPLMN.

2.6.1 UE Procedures

DHCP is enhanced so that an “ePDG selection indicator” can be returned to the UE when the UE performs DHCP negotiation after attaching to the WLAN and attempting to negotiate with a DHCP server to gain certain information (e.g., IP layer information such as IP address to use, DNS server IP addresses, etc.). A UE may utilize DHCP to discover the details of one or more ePDGs to connect to. A UE may perform such a DHCP operation/transaction regardless of whether DHCP is being used to also obtain an IP address (e.g., case where UE learns IP address via PCO, case where UE learns IP address through stateless address auto-configuration).

DHCP may convey one or a combination of the following different types of parameters relating to ePDG/ePDG selection:

-   -   IPv4 address of an ePDG server     -   IPv6 address of an ePDG server     -   FQDN of an ePDG server     -   Indication of one of the following:         -   UE must attempt to use only an HPLMN ePDG         -   UE must attempt to use only an RPLMN ePDG         -   UE must attempt to use an HPLMN ePDG, and can attempt to use             an RPLMN ePDG if the HPLMN ePDG is unavailable.         -   UE must attempt to use an RPLMN ePDG, and can attempt to use             an HPLMN ePDG if the HPLMN ePDG is unavailable.

A UE may, but need not, indicate its ability/intention/capability/support of ePDG connection/selection in order to receive ePDG related options/parameters from a DHCP server.

Table 16 presents an example where DHCPv4 and DHCPv6 options are defined for conveying ePDG IPv4 and IPv6 addresses, where XXX and YYY indicate reserved numerical values that each uniquely identify the new DHCP option. Similar encoding could be assumed for any of the above listed parameters relating to ePDG/ePDG selection.

2.6.2 Use of ePDG Selection Indicator

Use of the ePDG selection indicator operates in the same manner as described above in section 2.1.3.

2.7 Efficient ePDG Provisioning and Selection

PLMNs are sometimes identified by an FQDN that is not constructed from a PLMN ID as defined in 3GPP TS 23.002 (i.e. MCC and MNC). For example, a PLMN may purchase a service provider that was not a PLMN, so that until such time as the PLMN can operationally upgrade the infrastructure there will be a period of time that a PLMN is advertised using non-PLMN codes. One example method provides for a way for the HPLMN to configure this PLMN in the current data set even if a PLMN has LI requirements but advertises itself via a FQDN. In addition, a VPLMN may identify its ePDGs via FQDNs and a UE may only select an ePDG in a VPLMN using PLMN ID/code or Tracking Area (TA)/Location Area (LA), yet the FQDN is associated with an ePDG. This example method provisions the UE to select an ePDG using an FQDN to allow the VPLMN to meet its LI obligations via existing mechanisms.

2.7.1 Enhanced ePDG Selection Information

The data structure used with known ePDG provisioning is optimized for cases where the ePDG is located in the HPLMN. If the prevailing preference to have the ePDG located in country where the UE is roaming, the size of the previsioning data is enormous. Today, there are about 600 PLMNs and an operator may have to provision 600 PLMNs assuming none of the PLMN like their inbound roamers to select the ePDG in the HPLMN.

The following modifications (underlined) would enhance the known ePDG data structure:

-   -   List of <one or more ‘listentry’>     -   ‘Listentry’ contains “PLMN code” or “any_plmn” or “SP-FQDN” or         “Country code” and optionally per ‘listentry’ ‘FQDNformat’ or         ‘ePDGlocation’     -   ‘FQDNformat’ is one of “TA/LA derived” or “PLMN code derived” or         “ePDG FQDN”     -   ‘ePDGlocation’ is one of “mandatory” or “preferred” or “select         ePDG in HPLMN first”

The enhanced data structure allows for indicating exceptions to the ‘anyPLMN’ indicator by specifying the PLMN for which the ePDG needs to be selected in the HPLMN. This could reduce the number of PLMNs to be provisioned.

The enhanced data structure allows for indicating country code of countries where the ePDG needs to be selected in the country itself or, indeed, of countries that are okay with selecting an ePDG in the HPLMN, this data structure also allows for a reduction of the number of PLMNs to be provisioned.

In some PLMNs, ePDG are identified by an FQDN. The enhanced structure would allow to provision preferences for these PLMNs. Some PLMNs are identified by FQDN or NAI as opposed to be PLMN Identifier. The enhanced structure would allow to provision preferences for these PLMNs (in these cases the PLMN may indeed be known as a service provider).

The UE can be provisioned with less PLMN codes using this structure. Procedures are shown in Table 17 which details proposed changes to 3GPP TS 23.402.

Detailed stage 3 procedures and date structures are shown in Table 18. Proposed changes shown below are changes on top of current TS 24.312 (13.0.0).

2.8 IKE

In one example method, IKE is used to instruct the UE to select an ePDG in the VPLMN by the VPLMN when the UE has attached (i.e. has an RPLMN in memory) via 3GPP access to that PLMN. In addition, if the UE has not attached to a PLMN (i.e. the RPLMN has been deleted according to 3GPP TS 23.122 subclause 5), but has authenticated with a PLMN via WLAN, IKE is used to instruct the UE to select an ePDG in that VPLMN.

Where a UE does not use EAP for authentication, the UE may first select an incorrect ePDG (i.e. when the UE is not attached via 3GPP access). Upon receipt of an IKE_AUTH request message from the UE requesting the establishment of a tunnel, the ePDG proceeds with authentication and authorization. The basic procedure is described in 3GPP TS 33.402, while further details are provided in 3GPP TS 24.302.

During the UE's authentication and authorization procedure, the 3GPP AAA server provides to the ePDG an indication about the selected IP mobility mechanism (see 3GPP TS 29.273) and whether authentication should proceed due to the location from which the UE is attempting to establish a tunnel.

Either the ePDG or the HSS can be provisioned with information about LI preferences in the country where the UE resides. ePDG may use IP address to determine an approximation (i.e. country granularity) of the location of the UE. Other means may exist to determine UE location by ePDG or HSS.

In the tunnel establishment procedures, the ePDG can receive an error indication (e.g. DIAMETER_ERROR_non_VPLMN_ePDG_not_allowed) sent by the 3GPP AAA Server. The error indication means the network refuses service to the UE because the country or PLMN the UE is located does not support EPS services from non-3GPP access that are not handled via a ePDG in that country or PLMN. In this case, the ePDG shall include, in the IKE_AUTH response message, a Notify Payload with a Private Notify Message Type—“Current ePDG access to EPC not allowed in PLMN” or “Current ePDG access to EPC not allowed in country.”

The IKE_AUTH response message may further include one more IP addresses, SP FQDNs, NAIs, PLMN codes, ePDG FQDNs. These can be used for authentication purposes by the UE, enabling the UE to obtain service via an indicated ePDG or service provider and its ePDG.

As an alternative, the UE's authentication procedure may be successful, but the UE is not authorized to use the selected ePDG for any services (with the possible exception of emergency services). The indication that authentication is successful and a second indication that authorization has failed would allow a UE to trust any redirection information in the form of the one more IP addresses, SP FQDNs, NAIs, PLMN codes, or ePDG FQDNs.

A UE may attempt to connect to an ePDG but the UE may not be allowed to obtain services via that ePDG. Examples include the ePDG does not support the services requested (e.g., emergency) or the UE is in a location from which it is not allowed to obtain services via this ePDG or via this PLMN.

The ePDG may receive an indication from the HSS or AAA Server. The indication may be included in a Result code IE of the Authentication and Authorization Answer message. The indication may be a permanent failure, specified as follows in Table 19 which presents proposed changes to 3GPP TS 29.272.

The ePDG upon receiving the indication or due to configuration sends a second indication, e.g. “PLMN_NOT_ALLOWED” as shown in Table 20 which presents proposed changes to 3GPP TS 24.302.

3. UE Configuration

A block diagram of an example of a wireless communication device 1100, such as UE 602, 702, 802, 903 is shown in FIG. 11. The wireless communication device 1100 includes multiple components, such as a processor 1102 that controls the overall operation of the wireless communication device. Communication functions, including data and voice communications, are performed through a communication subsystem 1104 which includes a communication interface. Data received by the wireless communication device is decompressed and decrypted by a decoder 1106. The communication subsystem 1104 receives messages from and sends messages to a wireless network 1150. The wireless network 1150 may be any type of wireless network, including, but not limited to, data wireless networks, voice wireless networks, and networks that support both voice and data communications. A power source 1142, such as one or more rechargeable batteries or a port to an external power supply, powers the wireless communication device.

The processor 1102 interacts with other components, such as Random Access Memory (RAM) 1108, memory 1110, a display 1112 (which may be a touch-sensitive display), one or more actuators 1120, an auxiliary input/output (I/O) subsystem 1124, a data port 1126, a speaker 1128, a microphone 1130, short-range communications 1132, and other device subsystems 1134. User-interaction with a graphical user interface is performed through the touch-sensitive display 1112. Information, such as text, characters, symbols, images, icons, and other items that may be displayed or rendered on a portable electronic device, is displayed on the touch-sensitive display 1112 via the processor 1102. The processor 1102 may interact with an accelerometer 1136 that may be utilized to detect direction of gravitational forces or gravity-induced reaction forces.

To identify a subscriber for network access, the wireless communication device 1100 uses a Subscriber Identity Module or a Removable User Identity Module (SIM/RUIM) card 1138 for communication with a network, such as the wireless network 1150. Alternatively, user identification information may be programmed into memory 1110.

The wireless communication device 1100 includes an operating system 1146 and software programs or components 118, such as an instant messaging application 1144 that are executed by the processor 1102 and are typically stored in a persistent, updatable store such as the memory 1110. Additional applications or programs may be loaded onto the wireless communication device 1000 through the wireless network 1150, the auxiliary I/O subsystem 1124, the data port 1126, the short-range communications subsystem 1132, or any other suitable subsystem 1134.

A received signal such as a text message, an e-mail message, instant message or web page download is processed by the communication subsystem 1104 and input to the processor 1102. The processor 1102 processes the received signal for output to the display 1112 and/or to the auxiliary I/O subsystem 1124. A subscriber may generate data items, for example e-mail messages, which may be transmitted over the wireless network 1850 through the communication subsystem 1104. For voice communications, the overall operation of wireless communication device 1100 is similar. The speaker 1128 outputs audible information converted from electrical signals, and the microphone 1130 converts audible information into electrical signals for processing.

The touch-sensitive display 1112 may be any suitable touch-sensitive display, such as a capacitive, resistive, infrared, surface acoustic wave (SAW) touch-sensitive display, strain gauge, optical imaging, dispersive signal technology, acoustic pulse recognition, and so forth, as known in the art. A capacitive touch-sensitive display includes a capacitive touch-sensitive overlay. The overlay may be an assembly of multiple layers in a stack including, for example, a substrate, a ground shield layer, a barrier layer, one or more capacitive touch sensor layers separated by a substrate or other barrier, and a cover. The capacitive touch sensor layers may be any suitable material, such as patterned indium tin oxide (no).

One or more touches, also known as touch contacts or touch events, may be detected by the touch-sensitive display 1112. The processor 1102 may determine attributes of the touch, including a location of a touch. Touch location data may include an area of contact or a single point of contact, such as a point at or near a center of the area of contact. A signal is provided to a display controller (not shown) in response to detection of a touch. A touch may be detected from any suitable contact member, such as a finger, thumb, appendage, or other objects, for example, a stylus, pen, or other pointer, depending on the nature of the touch-sensitive display 1112. Multiple simultaneous touches may be detected.

One or more actuators 1120 may be depressed or activated by applying sufficient force to the actuators 1120 to overcome the actuation force of the actuator. The actuator(s) 1820 may provide input to the processor 1102 when actuated. Actuation of the actuator(s) 1820 may result in provision of tactile feedback.

4. Non-Limiting Embodiments

As will be appreciated by one skilled in the art, aspects of the present disclosure may be embodied as a system, method, or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit”,” “module”, or “system.”

The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.

Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer maybe connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.

These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 

What is claimed is:
 1. A method in a user equipment (UE) to select a second network node that is an Evolved Packet Data Gateway (ePDG) having UE request capabilities that allow discovery of details of one or more ePDGs for connection, the method comprising: attaching to a network; determining whether the network attached to is in selection information; if the network is in the selection information: constructing a fully qualified domain name (FQDN) for this network; and using the FQDN to obtain an Internet Protocol (IP) address of the second network node; and if the network is not in the selection information: sending a first message to a first network node, the first message including UE request capabilities indicating ePDG selection per the discovery; receiving a second message from the first network node, the second message including an indication that the UE attempts to connect using an ePDG belonging to a Registered Public Land Mobile Network (RPLMN); and selecting the second network node for connecting to a network based on the received indication.
 2. The method of claim 1, wherein the UE comprises a mobile equipment.
 3. The method of claim 2, wherein the UE further comprises a Universal Integrated Circuit Card (UICC).
 4. The method of claim 1, wherein the indication includes a Fully Qualified Domain Name (FQDN).
 5. The method of claim 4, wherein selecting the second network node based on the received indication further comprises selecting the ePDG in the RPLMN by constructing an operator identifier FQDN using a PLMN ID of a Public Land Mobile Network (PLMN) to which the user equipment is attached.
 6. The method of claim 1, wherein the first network node is a Domain Name Service (DNS) server.
 7. The method of claim 1, further comprising attaching to a Public Land Mobile Network (PLMN).
 8. A user equipment (UE) for selecting a second network node that is an Evolved Packet Data Gateway (ePDG) having UE request capabilities allow discovery of details of one or more ePDGs for connection to a network, the UE comprising: a processor that: attaches the UE to a network; determines whether the network attached to is in selection information; and if the network is in the selection information: constructs a fully qualified domain name (FQDN) for this network; and uses the FQDN to obtain an Internet Protocol (IP) address of the second network node; and a communication interface that: if the network is not in the selection information: sends a first message to a first network node, the first message including UE request capabilities indicating eDPG selection per the discovery; and receives a second message from the first network node, the second message including an indication that the UE attempts to connect using an ePDG belonging to a Registered Public Land Mobile Network (RPLMN); wherein, if the network is not in the selection information, the processor further selects a second network node for connecting to the network based on the received indication.
 9. The user equipment of claim 8, wherein the indication includes a Fully Qualified Domain Name (FQDN).
 10. The user equipment of claim 9, wherein selecting the second network node based on the received indication further comprises selecting the ePDG in the RPLMN by constructing an operator identifier FQDN using a PLMN ID of a Public Land Mobile Network (PLMN) to which the user equipment is attached.
 11. The user equipment of claim 8, wherein the first network node is a Domain Name Service (DNS) server.
 12. The user equipment of claim 8, wherein the processor and communication interface further attach the user equipment to a Public Land Mobile Network (PLMN).
 13. A computer program product for selecting a second network node that is an Evolved Packet Data Gateway (ePDG) having UE request capabilities that allow discovery of details of one or more ePDGs for a user equipment to connect to a network, the computer program product comprising: a non-transitory storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for: attaching to a network; determining whether the network attached to is in selection information; if the network is in the selection information: constructing a fully qualified domain name (FQDN) for this network; and using the FQDN to obtain an Internet Protocol (IP) address of the second network node; and if the network is not in the selection information: sending a first message to a first network node, the first message including UE request capabilities indicating ePDG selection per the discovery; receiving a second message from the first network node, the second message including an indication that the UE attempts to connect using an ePDG belonging to a Registered Public Land Mobile Network (RPLMN); and selecting the second network node for connecting to a network based on the received indication.
 14. The computer program product of claim 13, wherein the indication includes a Fully Qualified Domain Name (FQDN).
 15. The computer program product of claim 13, wherein selecting the second network node based on the received indication further comprises selecting the ePDG in the RPLMN by constructing an operator identifier FQDN using a PLMN ID of a Public Land Mobile Network (PLMN) to which the user equipment is attached.
 16. The computer program product of claim 13, wherein the first network node is a Domain Name Service (DNS) server.
 17. The computer program product of claim 13, further comprising instructions for attaching to a Public Land Mobile Network (PLMN). 